Syringe



March 27, 1945- H. H. BEASLEY ET A| SYRINGE Filed April s, 1944 PatentedMar. 27, 1945 pflvlrizoy STATES PATENT oF'FI'cE SYRINGE Harold HolmyardBeasley, Portishead, and Albert Weeks, Bristol, England ApplicationApril 6, 1944, Serial No. 529,718

5 Claims.

, This invention relates tosyringes for dispensing liquid in'smallquantities through restricted jections or discharges ofv accuratelyuniform volume without recharging and without the In Great Britain May6, 1943 necessity of visual inspection of the Acontents v` of thesyringe a1; each operation. Another ob-ject of this invention is toprovide a hypodermic or like syringe adapted to deliver a succession ofdischarges or injections without recharging but which will indicateautomatically when the stage is reached at which there is insufficientliquid available to provide a full charge for delivery by the syringe'.A still further object of this invention is toprovide a multi-shothypodermic syringe which is convenient to handle and adapted to be usedin such manner that the act of inserting the needle and the act ofadministering the charge does not necessitate changing the hand ordigital grip on the syringe.

According to this invention'a syringe for eject ing an accuratelymeasured predetermined quantity of liquid through a restricted orificesuch as e. g. an inoculation needle or a fine bore nozzle. ischaracterized in that it incorporates a rellable reservoir having acapacity several times the volume of liquid to be discharged at eachoperation of the syringe and means to discharge the contents of suchreservoir by a sucv cession of operationsl each delivering apredetermined accurate measured quantity'of liquid.

In carrying on`form of the invention into practice as' applied t0afhy'podermic syringea tubular needle holder isfitted asa radial orunit-lateral projection of a base member which may be in' theformfof'fa' cylindricalJ body of metal or other suitable material.'Fixed in its centre is anv upstanding plunger over the upper 'm part ofwhich is slid a sleeve closed at its top and formedY at its lower orinner end with a grooved ange to which is secured one mouth of avflexible rubber sac, a further mouth of which is similarly secured to aboss on the said cylin drical: body. The sac is protected by asuitable55 circumferentially grooved flange 5a to receive' housing tted onto thesaidbody and aperturedto expose the upper end of .thesaid sleeve Aform-anipulation. The needle holder accommodates a non-return valve andcommunicates by a radial passage with an axial bore of the said plunger;

such bore communicating with the interior of the top of the sleeve sothat liquid vdrawn intov the top of the sleeve yby sliding the sleeveaway from the said body is discharged through saidv bore into the needleholder and needle upon pressing home the sleeve. The liquid is drawninto the sleeve via a radial port in the plunger and which communicateswith the axial bore, this radial port being exposed to the interior ofthe sac when the sleeve is fully extended. A

filling plug can be provided in the said body'fo'rY refilling the sac.'

In order that this invention may be clearly understood and readilycarried into eilect a drawing is appended hereto illustrating van em-jbodiment thereof, 'and wherein,

Fig. 1 is a 'sectional elevation '.to! afsome' what enlarged scale ofthe hypodermic syringe" in its normal condition readyv for use, AamiFig. 2 is a sectional elevation to the same scale showing the syringeafter it has b'een charged ready for' an injection.

actuated to measure a quantity of liquid t0 beejected therefrom, andwhen making an injec tion, so that it is protected internally againstthe risk of forming air bubbles and also against the harmful eiects ofair and germs carried by the air. For this purpose the container for theliq-v uid is a iiexible rubbersac I` of bulbous or tubu-I lar form-'openat top and bottom where it is se-A cured in an air-tight manner by rings2 and 3 which may be formed integrally with the sac land which clamp thetwo mouths ofthe sac closely to the body part 4 and sleeve 5respectively.

The body t is circular in plan and' may be metal die-casting or othersuitable durable" material raving a circumferenti'ally grooved boss@which receives 'the appropriate neck of ther sac andthe clamping ring2, and in the centre of thisA body is fixed one end of a stem 1, theother 'end of which is machined accurately to form a i plunger 'lahaving a close sliding t in the sleeve 5, the top of the plunger 'lanormally abutting against the closed" top of the sleeve 5. The sleeve 5-is formed at its'inner end with a the appropriate neck of the sa'c I andits clamping ring 3, and the outer end of the sleeve iscircumferentially grooved as at 5b or otherwise suitably shaped toafford a peripheral part which can be gripped firmly between a thumb andfinger to enable the sleeve to be pulled along the plunger away from thebody 4 for drawing into the outer end of the sleeve a charge of liquidabstracted from the sac I.

The liquid is drawn into the sleeve 5 from the l sac I- via a port inthe form of a radial bore 8 in the plunger Ia and a bore 9 passingaxially through the stem 'I to the outer end of its plunger 1a, theinner end of this axial bore terminating at the inner end of a radialpassage Ill in the body 4, the other end of this radial passagecommunieating with a bore IIa formed in an elbow or union II fixed inthe periphery of the body 4. This elbow or union II has a threaded outerend part I Ib onto which is threaded a nozzle I2 adapted at its free endto receive the cap I3a of the hypodermic needle I3.

The sac I is protected by a moulded housing I4 threaded by a neck I4a atits lower end onto a reduced diameter part 4a of the body 4, suchhousing having a part spherical end I 4b to accommodate the sac I whencollapsed or in its normal idle position. The upper part of this housingis preferably of truncated conical form as shown, with a centralaperture to receive the sleeve 5. When the sleeve 5 is fully extendedrelatively to the plunger its flange 5a will abut against the annularupper end of the housing I4, and the position of the said port 8 in theplunger is such that it will be uncovered and exposed to the interior ofthe sac when the sleeve is thus fully extended, and consequently owingto the vacuum created inside the end of the sleeve by pulling the sleeve'5 to the said extended position, some of the liquid in the sac willflow into and fill the space in the sleeve between the outer ends of theplunger and the sleeve as shown in Fig. 2. The syringe is now ready tomake an injection by inserting the needle and pressing the sleevetowards the body 4.

Upon pressing the sleeve 5 toward the body 4 liquid will at first passback freely into the sac via the bore 9 and port 8 until the port iscovered by the sleeve 5 whereupon the liquid in the sleeve will beforced into the radial passage I and from thence through the needle.

It is important to prevent the ingress of extraneous air into thesyringe during any period of its operation and for this purpose anysuitable form of non-return valve can be provided, the preferredarrangement being to fitv in the nozzle I2 a non-returnvalve I5 of thetype used with inner tubes of cycle tyres in which the valve stem issurrounded by a piece of rubber tubing.

To facilitate lapping of the bore of the` sleeve the outer end of suchsleeve may be enlarged slightly in its internal diameter for an axialdistance suiiicient to receive the port 8 and also it is preferred toflare the outer end of the bore 'I as at 1b to ensure a smooth flow ofliquid into the bore 1.

To enable the sac to be re-charged a lling hole I6 closed by a screwplug I1 is formed in the body 4, and the base of this body is preferablydished as at I8 so that the head of the plug I1 will not prevent thesyringe from being stood upon any suitable base and also to facilitatemanipulation and holding of the syringe. For this latter purpose theouter end of the sleeve 5 is also preferably dished as indicated by thereference numeral I9.

When charging the sleeve and using the syringe it is preferable toinvert the syringe as shown in Fig. 2. Owing to the sac I being anairtight rubber member it will adapt itself readily to the movements ofthe sleeve 'I and also will conform readily to differences in internaland external pressures due to the progressive exhaustion of itscontents. Also the sac is easily replaced by a new sac, and likewise byunscrewing the nozzle I2 it is a simple matter to replace the valve I5or its rubber tubing.

If desired a non-return inlet valve may be provided in a suitablydisposed opening leading from the interior of the sac to the bore 9 inthe stem 'I and plunger Ia for the purpose of enabling the liquid to bedrawn from the reservoir past the nonqeturn valve into the sleeve 5through the bore 9. This would form an alternative to using the sleeveto act as a valve by uncovering and covering the port 8.

Should it be required to make an unusually large number of injectionswithout recharging the sac I, the filling hole I6 may have an adaptorcoupling tted therein to connect one end of a length of tubing 'leadingfrom a bottle or other receptacle containing a considerable quantity ofthe liquid so that injections can be carried out over a very protractedperiod. This receptacle may be iiexibleor may be closed by a exiblediaphragm. Normally, in the use of the syringe when the supply of liquidin the sac is exhausted or, if there is insufficient liquid in the sacto recharge the sleeve, the sleeve will not remain in the fully extendedposition when pulled outwards, but will spring back toward its normalposition under the influence of atmospheric pressure,

.thereby indicating unmistakably that a recharging of the sac isnecessary.

This invention provides an improved form of syringe which is capable ofdelivering a number of measured charges without the need to rell aftereach discharge. f

The ability to give a Anumber of measured charges without refilling isof value in the Acase of mass inoculation, and is of particular valueunder field conditions where a number of casualties may have to be dealtwith in difficult circumstances. An instrument according to theinvention may be made to satisfy the following surgical and manipulativerequirements:

(a) The instrument will hold `an adequate number of charges, which arecompletely protected against the ingress of foreign matter, even air,and should be proof against leakage of the contents.

(bi) The measured charges will be uniform and accurate in quantity andmay be independent of visual inspection as the instrument may be used inldarkness or poor light.

(c) Automatic indication will be given of exhaustion of the bulk supply.

(d) The instrument `isfconvenient to handle and the act of inserting theneedle and administering' the charge neednot involve changing the handgrip on the instrument.

We claim:

l. A syringe for delivering a multiplicity of liquid charges ofpredetermined volume through an orince comprising a base, a. plungermounted on the base, a. sleeve slidably mounted over said plunger andclosed at lits upper end, a liquid reservoir comprising a resilientflexible tube of liquid-impervious material surrounding plunger andhaving its lower end sealed to said base and its upper end sealed to theopen end of saidv said sleeve, a nozzle attached to said base, a.

zle, a port in the side of said plunger Acommunieating with said liquidpassage, said port being positioned so that it is uncovered onlywhensaid sleeve is drawn out to a predetermined position relative to saidplunger and being covered when said sleeve is depressed upon saidplunger, whereby liquid cannot be withdrawn from said reservoir into theclosed end of said sleeve until said sleeve has been withdrawn to saidpredetermined posi-v tion, and a lnon-return valve in said nozzle toprevent intake of air into said syringe when said sleeve is drawn out.

2. A syringe as recited in claim 1 having a rigid housing over saidreservoir, said housing having an aperture adapted to' permit said rigidsleeve to extend therefrom and to' guide said sleeve.

3. A syringe as recited in claim 1 in which said liquid reservoircomprises a tube of rubber.

. 4. A syringe as recited in claim 1 in which said base is provided witha liquid inlet and aclosure for said inlet.

5. A syringe for delivering a multiplicity of liquid ycharges ofpredetermined volume through an oriiice comprising a base, a plungermounted on the base, a sleeve slidably mounted over said plunger andclosed at its upper end, a liquid reservoir comprising a resilientflexible tube of liquid-impervious material surrounding said plunger andhaving its lower end sealed to said base and its upper end sealed to theopen end of said sleeve, a nozzle attached to said base, a

liquid passage extending through said plunger and said base andcommunicating with said nozzle, a port in the side of said plungercommunicating with said liquid passage, said reservoir normal- 1ytendingto confine the liquid about said plunger and in the absence ofpressure normally tending to force said sleeve to its most extendedposition, and a non-return valve in said nozzle to prevent intake of airinto said syringe when said sleeve is drawn out.

HAROLD HOLMYARD BEASLEY. ALBERT WEEKS.

